Have You Heard About “Mastered For iTunes”?

Have you heard the term mastered for iTunes yet? Recently there has been a thing in the news (albeit a small techie segment) about certain music tracks in a new section in iTunes called Mastered for iTunes. What does it mean?

Well first it helps to understand what "not" mastered for iTunes means, which is how all of their music has sounded since their inception. It comes down to this - music files that stream easily over the internet and play on your device are "lossy, " which means lots of the digital information contained in the original wav file is removed and the remaining data compressed (not the same as audio compression, btw) to a much smaller file. This is done in such a way that most people don't even hear a difference (between the CD version and the mp3/AAC version) most of the time. And if they do, they are happy to trade that difference for the convenience of having the music on their iPod, streaming online faster, etc.

But here is an interesting factoid. Recording studios, even home recording studios these days, record most often at a bit rate of 24 bits. But CD standards require the file to be at 16 bits, which technically is not "lossy," but is still a sort of a step down from the 24 bit version in the studio. Then to make the music available for iTunes, most conversion processes just use the 16 bit version from the CD.

The mastered for iTunes versions of songs are created, using a special software that iTunes is making available only to some engineers at the moment, uses the 24-bit version of the audio as the source and creates a still-lossy stream-able file, but a better one, at least for those who can hear the difference (I have my doubts about how big that number really is).